The campaign of John McCain went head-to-head with Madonna today after the 50-year-old pop diva appeared to compare the Republican candidate to Hitler and Robert Mugabe.

Madonna, who kicked off her “Sticky and Sweet” world tour at the Millennium Stadium in Cardiff yesterday, made the swipe during a performance of Get Stupid, when Mr McCain’s image was flashed up alongside images of the Führer and Zimbabwean dictator, as well as destruction and global warming.

In a none-too-subtle contrast, Barack Obama was bracketed in a subsequent sequence alongside Mahatma Gandhi, John Lennon and Al Gore.

A McCain campaign spokesman, Tucker Bounds, condemned the segment. “The comparisons are outrageous, unacceptable and crudely divisive all at the same time,” Mr Bounds said.